Heterogeneous networks include a relatively low-power base transceiver terminal or station, sometimes referred to as a “pico” or “femto” cell located within a wireless communications coverage footprint of a relatively high-power base transceiver station. The relatively high-power base transceiver station is sometimes referred to as a “macro” cell and can poses interference to mobile communications devices in communication with the base transceiver station of the relatively low-power or pico cell. For example, reception of downlink communications from a base transceiver station of a pico cell to a mobile communications device positioned with a region of overlapping wireless coverage between the macro cell and the pico cell, might be interfered with by downlinks from the macro cell to other mobile communications devices. Such unwanted interference might render the pico cell unusable within certain regions, for example, reducing an effective footprint of the pico cell. Another consequence includes a reduction in operational bandwidth resulting from a reduced signal to noise and interference ratio. The signal refers to a downlink from pico cell; whereas, noise and interference includes other downlinks and control signals from macro cell.
In order to improve the performance for mobile communication devices connected to such low power cells overlapped by macro cells, the macro cell can be operated to essentially stop transmitting during certain periods of time, e.g., certain subframes of a frame. Release 10 of the third-generation partnership project (“3GPP”), long term evolution (“LTE”) standard provides a feature to reduce the likelihood of such interference, referred to as enhanced inter-cell interference coordination (“eICIC”). The standard specifies a limited number of almost blank subframes within each downlink communication frame, during which the macro cell base transceiver station only transmits a very limited amount of information, such as control information as may be necessary to maintain communications. The micro or femto cell is configured to coordinate downlink information to mobile communications devices during such almost blank subframes.
Mobile communications devices typically provide a base transceiver station of a cell with some measure of a wireless channel state, sometimes referred to as a channel assessment in the form of a channel quality indicator. The base transceiver station, for example, can use such channel quality indicators to establish a preferred communications rate, such as a maximum channel bit rate, by which the mobile communications device can communicate with the base transceiver station of the cell. For enhanced inter-cell interference coordination, communications devices compliant with release 10 of the 3GPP LTE standard are configured to perform channel state assessments and provide channel quality indicators with respect the almost blank subframes, the non-almost blank subframes, or both.